190 SODIUM CARBONATES 



of the solid salt (C 2 H 5 ONa), is a colourless, syrupy liquid, 

 becoming brown by keeping, and is used as a caustic. 



2. The chloride, sulphate, and nitrate act as soluble crys- 

 talloids, are mildly antiseptic, febrifuge, and refrigerant ; 

 small doses are slightly diuretic, while large doses are saline 

 purgatives. 



3. The borate, benzoate, hyposulphite, sulpho-carbolate, 

 chlorate, salicylate, and valerianate resemble their acid 

 radicle rather than their base. 



SODIUM HYDROXIDE. Sodium Hydrate. Caustic Soda. 

 NaHO. 



SODIUM CARBONATE. Sodii Carbonas. Carbonate of Soda. 

 Na 2 C0 3 .10Aq. 



SODIUM BICARBONATE. Sodii Bicarbonas. Bicarbonate of 

 Soda. NaHC0 3 . 



Sodium hydrate and solution of caustic soda resemble in 

 their preparation and general properties the corresponding 

 potassium compounds, but are little used in veterinary 

 practice. 



The carbonate was formerly obtained by lixiviating the 

 ashes of marine plants, and from the native sesqui-carbonate 

 or natron found as an efflorescence on the margins of lakes 

 in warm climates. It is now obtained from common salt, 

 by heating it in furnaces with sulphuric acid ; the sulphate 

 thus prepared is converted into sulphide, and thence into 

 carbonate, by roasting with coal or slack and limestone ; 

 lixiviating, calcining, and crystallising. From a saturated 

 solution of this soda ash there separate large transparent, 

 colourless, laminar, rhombic crystals of hydrated carbonate 

 (Na 2 C0 3 .10Aq.). The water may be driven off by heating 

 to 120 Fahr., when the dried granular sodium carbonate 

 remains. The carbonate in its several forms is alkaline to 

 taste and reagents, efflorescent, and soluble in one or two 

 parts of water. 



The bicarbonate produced by saturating the carbonate 

 with carbonic anhydride occurs as a white crystalline powder, 

 or aggregation of irregular opaque scales, has a saline, slightly 



